The Principal Investigator has purified a phospholipid from human placenta that is a potent activator of protein kinase C and an inhibitor of cAMP-dependent protein kinase. By HPLC and TLC criteria and by its mode of action it appears to be a novel phospholipid not previously described. We need to determine its precise chemical structure and the UCSF Mass Spectrometry Facility is a key resource to assist in this endeavor.